The semiconductor device using silicon carbide (SiC) is conventionally known (for example, International Publication No. WO01/018872 (hereinafter referred to as Patent Document 1)). Patent Document 1 discloses a configuration of a silicon carbide semiconductor device in which a buffer layer made of SiC is formed on a 4H-polytype SiC substrate having a plane orientation of approximately {03-38}. The plane having a plane orientation of {03-38} (a {03-38} plane) is inclined about 35° with respect to the <0001> axial direction to which a micropipe and a screw dislocation extend. Accordingly, in the case where a buffer layer is formed on the above-described SiC substrate, the micropipe and screw dislocation in the SiC substrate extend in an inclined direction and disappear on the side surface of the buffer layer and the like. This prevents the micropipe and screw dislocation from extending to the epitaxial layer (active layer) formed on the buffer layer, with the result that the epitaxial layer having less defects and an excellent flatness can be obtained. Furthermore, in Patent Document 1, it is preferable that the above-described buffer layer has a thickness of not less than 0.1 μm and not more than 15 μm.    Patent Document 1: International Publication No. WO01/018872